Expression And Localization Of Diacylglycerol Kinase ζ,Protein Kinase C δ And Tis21 In The Developing Rat Brain

Objective:To investigate the spatio-temporal expression patterns and the relationship of diacylglyceral kinase ζ( DGKζ), PKCδ and Tis21 protein in the developing rat brain.Methods:Serial sections of five rat embryos each day from E9.5 to E18.5 were stained immunohistochemically to detect the expression of DGKζ, p-PKC δ and Tis21 in rat embryonic brains. Western blotting was performed to examine the expression of DGKζ,p-PKCδ, PKCδ and Tis21 in 22 rat embryonic brains at E11.5, E12.5, E14.5, E16.5 and E18.5.Results:1.Immunohistochemistry staining showed that p-PKCδ and Tis21 were positively expressed in the neuroepithelium of neural groove while DGKζ was negtively expressed at E9.5. DGKζ, p-PKCδ and Tis21 were positively expressed in the neuroepithelium of brain vesicles at E10.5 and E11.5. At E12.5, DGKζ, p-PKCδ and Tis21 were positively expressed in the neuroepithelum of telencephalon, diencephalon, ventral mesencephalon and pons. DGKζ was positively expressed in dorsal mesencephal, isthmus and cerebellar primordium, while the expression of p-PKCδ and Tis21 was not observed until E13.5. At E13.5, the expression of all of these three proteins was positive in neuroepithelium and differentiating field of hippocampus, pallidum, septal and rhinencephalic and negative in neocortex. At E14.5, with the positive expression extending to neocortex and choroid plexus, DGKζ was expressed in the nervous tissue of whole brain. The expression of p-PKCδ and Tis21 only extended to tectum and choroid plexus. DGKζ expression pattern happened to p-PKCδ and Tis21 at E15.5. At E16.5-E18.5, their expression became weaker and was restricted to the cerebellum germinal layer and pontine nucleus. DGKζ, and p-PKCδ was expressed in cytoplasm of neuroepithelial cells, or in both cytoplasm andnucleus.2.Western blotting showed that the expression of DGKζ and TIS21 protein increased gradually at E11.5, E12.5 and E14.5, and decreased gradually at E16.5 and E18.5. The expression was significantly increased at E12.5 compared with E11.5. The ratio of p-PKCδ/PKCδ showed that the change of PKCδ activity had the same tendency with DGKζexpression.Conclusion:1.The spatio-temporal expression of DGKζ, p-PKCδ and Tis21 conforms with the development pattern of rat embryonic brain. The expression pattern of DGKζ is a little different from that of p-PKCδ and Tis21, but they overlap at E15.5. All of these suggest that DGKζ, p-PKCδ and Tis21 involve collaboratively in the development of rat brain.2.The expression of DGKζ and TIS21 protein and the activity of PKCδ are significantly increased at E12.5 and E14.5, consistently with the time of neurogenesis in rat embryonic brain. DGKζ and p-PKCδ are expressed in both cytoplasm and nucleus of neuroepithelial cells. All of these suggest that nuclear DGKζ and PKCδ play the roles in anti-proliferation and the induction of differentiation, and they take part in regulating the development of the embryonic brain via DGKζ/Tis21 and PKCδ/Tis21 signaling pathway.